How do you replace your rope on a 9.8 Mercury outboard Motor?

If your recoil spring is still working properly, it's fairly easy. Remove the starter sheave assembly, lay it upside down on the bench. Note where the old rope is anchored, remove any remaining rope. While holding assembly housing from turning, wind sheave in a counter clockwise direction until spring is completely tensioned. Carefully, let the sheave rotate clock wise about one revolution. Continue the rotation until the anchor pocket in the sheave lines up with the roller and outlet hole located in the housing. While holding the sheave assembly in this position, ( the spring is under tension ),thread the replacement rope into the anchor pocket and out through the housing outlet, pull snug. Tie a loose, temporary knot in rope, and allow spring to wind the rope back into the housing. Install the handle on rope end and untie knot. Allow rope to be wound back into the housing and pull several times to check operation. Note, if any disassembly is required, be advised that there are quite a few loose parts that make up this particular re-wind assembly. In this case, I would recommend purchasing a repair manual, or taking the assembly to a repair facility.